CDP: Filter out non-printable characters

[tcpdump] / util-print.c

/*
 * Copyright (c) 1990, 1991, 1993, 1994, 1995, 1996, 1997
 *      The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code distributions
 * retain the above copyright notice and this paragraph in its entirety, (2)
 * distributions including binary code include the above copyright notice and
 * this paragraph in its entirety in the documentation or other materials
 * provided with the distribution, and (3) all advertising materials mentioning
 * features or use of this software display the following acknowledgement:
 * ``This product includes software developed by the University of California,
 * Lawrence Berkeley Laboratory and its contributors.'' Neither the name of
 * the University nor the names of its contributors may be used to endorse
 * or promote products derived from this software without specific prior
 * written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

/*
 * txtproto_print() derived from original code by Hannes Gredler
 * (hannes@juniper.net):
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that: (1) source code
 * distributions retain the above copyright notice and this paragraph
 * in its entirety, and (2) distributions including binary code include
 * the above copyright notice and this paragraph in its entirety in
 * the documentation or other materials provided with the distribution.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
 * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
 * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <netdissect-stdinc.h>

#include <sys/stat.h>

#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif
#include <ctype.h>
#include <stdio.h>
#include <stdarg.h>
#include <stdlib.h>
#include <string.h>

#include "netdissect.h"
#include "ascii_strcasecmp.h"
#include "timeval-operations.h"

int32_t thiszone;               /* seconds offset from gmt to local time */

/*
 * timestamp display buffer size, the biggest size of both formats is needed
 * sizeof("0000000000.000000000") > sizeof("00:00:00.000000000")
 */
#define TS_BUF_SIZE sizeof("0000000000.000000000")

#define TOKBUFSIZE 128

/*
 * Print out a character, filtering out the non-printable ones
 */
void
fn_print_char(netdissect_options *ndo, u_char c)
{
        if (!ND_ISASCII(c)) {
                c = ND_TOASCII(c);
                ND_PRINT((ndo, "M-"));
        }
        if (!ND_ISPRINT(c)) {
                c ^= 0x40;      /* DEL to ?, others to alpha */
                ND_PRINT((ndo, "^"));
        }
        ND_PRINT((ndo, "%c", c));
}

/*
 * Print out a null-terminated filename (or other ascii string).
 * If ep is NULL, assume no truncation check is needed.
 * Return true if truncated.
 * Stop at ep (if given) or before the null char, whichever is first.
 */
int
fn_print(netdissect_options *ndo,
         register const u_char *s, register const u_char *ep)
{
        register int ret;
        register u_char c;

        ret = 1;                        /* assume truncated */
        while (ep == NULL || s < ep) {
                c = *s++;
                if (c == '\0') {
                        ret = 0;
                        break;
                }
                if (!ND_ISASCII(c)) {
                        c = ND_TOASCII(c);
                        ND_PRINT((ndo, "M-"));
                }
                if (!ND_ISPRINT(c)) {
                        c ^= 0x40;      /* DEL to ?, others to alpha */
                        ND_PRINT((ndo, "^"));
                }
                ND_PRINT((ndo, "%c", c));
        }
        return(ret);
}

/*
 * Print out a counted filename (or other ascii string).
 * If ep is NULL, assume no truncation check is needed.
 * Return true if truncated.
 * Stop at ep (if given) or after n bytes, whichever is first.
 */
int
fn_printn(netdissect_options *ndo,
          register const u_char *s, register u_int n, register const u_char *ep)
{
        register u_char c;

        while (n > 0 && (ep == NULL || s < ep)) {
                n--;
                c = *s++;
                if (!ND_ISASCII(c)) {
                        c = ND_TOASCII(c);
                        ND_PRINT((ndo, "M-"));
                }
                if (!ND_ISPRINT(c)) {
                        c ^= 0x40;      /* DEL to ?, others to alpha */
                        ND_PRINT((ndo, "^"));
                }
                ND_PRINT((ndo, "%c", c));
        }
        return (n == 0) ? 0 : 1;
}

/*
 * Print out a null-padded filename (or other ascii string).
 * If ep is NULL, assume no truncation check is needed.
 * Return true if truncated.
 * Stop at ep (if given) or after n bytes or before the null char,
 * whichever is first.
 */
int
fn_printzp(netdissect_options *ndo,
           register const u_char *s, register u_int n,
           register const u_char *ep)
{
        register int ret;
        register u_char c;

        ret = 1;                        /* assume truncated */
        while (n > 0 && (ep == NULL || s < ep)) {
                n--;
                c = *s++;
                if (c == '\0') {
                        ret = 0;
                        break;
                }
                if (!ND_ISASCII(c)) {
                        c = ND_TOASCII(c);
                        ND_PRINT((ndo, "M-"));
                }
                if (!ND_ISPRINT(c)) {
                        c ^= 0x40;      /* DEL to ?, others to alpha */
                        ND_PRINT((ndo, "^"));
                }
                ND_PRINT((ndo, "%c", c));
        }
        return (n == 0) ? 0 : ret;
}

/*
 * Format the timestamp
 */
static char *
ts_format(netdissect_options *ndo
#ifndef HAVE_PCAP_SET_TSTAMP_PRECISION
_U_
#endif
, int sec, int usec, char *buf)
{
        const char *format;

#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
        switch (ndo->ndo_tstamp_precision) {

        case PCAP_TSTAMP_PRECISION_MICRO:
                format = "%02d:%02d:%02d.%06u";
                break;

        case PCAP_TSTAMP_PRECISION_NANO:
                format = "%02d:%02d:%02d.%09u";
                break;

        default:
                format = "%02d:%02d:%02d.{unknown}";
                break;
        }
#else
        format = "%02d:%02d:%02d.%06u";
#endif

        snprintf(buf, TS_BUF_SIZE, format,
                 sec / 3600, (sec % 3600) / 60, sec % 60, usec);

        return buf;
}

/*
 * Format the timestamp - Unix timeval style
 */
static char *
ts_unix_format(netdissect_options *ndo
#ifndef HAVE_PCAP_SET_TSTAMP_PRECISION
_U_
#endif
, int sec, int usec, char *buf)
{
        const char *format;

#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
        switch (ndo->ndo_tstamp_precision) {

        case PCAP_TSTAMP_PRECISION_MICRO:
                format = "%u.%06u";
                break;

        case PCAP_TSTAMP_PRECISION_NANO:
                format = "%u.%09u";
                break;

        default:
                format = "%u.{unknown}";
                break;
        }
#else
        format = "%u.%06u";
#endif

        snprintf(buf, TS_BUF_SIZE, format,
                 (unsigned)sec, (unsigned)usec);

        return buf;
}

/*
 * Print the timestamp
 */
void
ts_print(netdissect_options *ndo,
         register const struct timeval *tvp)
{
        register int s;
        struct tm *tm;
        time_t Time;
        char buf[TS_BUF_SIZE];
        static struct timeval tv_ref;
        struct timeval tv_result;
        int negative_offset;
        int nano_prec;

        switch (ndo->ndo_tflag) {

        case 0: /* Default */
                s = (tvp->tv_sec + thiszone) % 86400;
                ND_PRINT((ndo, "%s ", ts_format(ndo, s, tvp->tv_usec, buf)));
                break;

        case 1: /* No time stamp */
                break;

        case 2: /* Unix timeval style */
                ND_PRINT((ndo, "%s ", ts_unix_format(ndo,
                          tvp->tv_sec, tvp->tv_usec, buf)));
                break;

        case 3: /* Microseconds/nanoseconds since previous packet */
        case 5: /* Microseconds/nanoseconds since first packet */
#ifdef HAVE_PCAP_SET_TSTAMP_PRECISION
                switch (ndo->ndo_tstamp_precision) {
                case PCAP_TSTAMP_PRECISION_MICRO:
                        nano_prec = 0;
                        break;
                case PCAP_TSTAMP_PRECISION_NANO:
                        nano_prec = 1;
                        break;
                default:
                        nano_prec = 0;
                        break;
                }
#else
                nano_prec = 0;
#endif
                if (!(netdissect_timevalisset(&tv_ref)))
                        tv_ref = *tvp; /* set timestamp for first packet */

                negative_offset = netdissect_timevalcmp(tvp, &tv_ref, <);
                if (negative_offset)
                        netdissect_timevalsub(&tv_ref, tvp, &tv_result, nano_prec);
                else
                        netdissect_timevalsub(tvp, &tv_ref, &tv_result, nano_prec);

                ND_PRINT((ndo, (negative_offset ? "-" : " ")));

                ND_PRINT((ndo, "%s ", ts_format(ndo,
                          tv_result.tv_sec, tv_result.tv_usec, buf)));

                if (ndo->ndo_tflag == 3)
                        tv_ref = *tvp; /* set timestamp for previous packet */
                break;

        case 4: /* Default + Date */
                s = (tvp->tv_sec + thiszone) % 86400;
                Time = (tvp->tv_sec + thiszone) - s;
                tm = gmtime (&Time);
                if (!tm)
                        ND_PRINT((ndo, "Date fail  "));
                else
                        ND_PRINT((ndo, "%04d-%02d-%02d %s ",
                               tm->tm_year+1900, tm->tm_mon+1, tm->tm_mday,
                               ts_format(ndo, s, tvp->tv_usec, buf)));
                break;
        }
}

/*
 * Print a relative number of seconds (e.g. hold time, prune timer)
 * in the form 5m1s.  This does no truncation, so 32230861 seconds
 * is represented as 1y1w1d1h1m1s.
 */
void
relts_print(netdissect_options *ndo,
            int secs)
{
        static const char *lengths[] = {"y", "w", "d", "h", "m", "s"};
        static const int seconds[] = {31536000, 604800, 86400, 3600, 60, 1};
        const char **l = lengths;
        const int *s = seconds;

        if (secs == 0) {
                ND_PRINT((ndo, "0s"));
                return;
        }
        if (secs < 0) {
                ND_PRINT((ndo, "-"));
                secs = -secs;
        }
        while (secs > 0) {
                if (secs >= *s) {
                        ND_PRINT((ndo, "%d%s", secs / *s, *l));
                        secs -= (secs / *s) * *s;
                }
                s++;
                l++;
        }
}

/*
 *  this is a generic routine for printing unknown data;
 *  we pass on the linefeed plus indentation string to
 *  get a proper output - returns 0 on error
 */

int
print_unknown_data(netdissect_options *ndo, const u_char *cp,const char *ident,int len)
{
        if (len < 0) {
          ND_PRINT((ndo,"%sDissector error: print_unknown_data called with negative length",
                    ident));
                return(0);
        }
        if (ndo->ndo_snapend - cp < len)
                len = ndo->ndo_snapend - cp;
        if (len < 0) {
          ND_PRINT((ndo,"%sDissector error: print_unknown_data called with pointer past end of packet",
                    ident));
                return(0);
        }
        hex_print(ndo, ident,cp,len);
        return(1); /* everything is ok */
}

/*
 * Convert a token value to a string; use "fmt" if not found.
 */
const char *
tok2strbuf(register const struct tok *lp, register const char *fmt,
           register u_int v, char *buf, size_t bufsize)
{
        if (lp != NULL) {
                while (lp->s != NULL) {
                        if (lp->v == v)
                                return (lp->s);
                        ++lp;
                }
        }
        if (fmt == NULL)
                fmt = "#%d";

        (void)snprintf(buf, bufsize, fmt, v);
        return (const char *)buf;
}

/*
 * Convert a token value to a string; use "fmt" if not found.
 */
const char *
tok2str(register const struct tok *lp, register const char *fmt,
        register u_int v)
{
        static char buf[4][TOKBUFSIZE];
        static int idx = 0;
        char *ret;

        ret = buf[idx];
        idx = (idx+1) & 3;
        return tok2strbuf(lp, fmt, v, ret, sizeof(buf[0]));
}

/*
 * Convert a bit token value to a string; use "fmt" if not found.
 * this is useful for parsing bitfields, the output strings are seperated
 * if the s field is positive.
 */
static char *
bittok2str_internal(register const struct tok *lp, register const char *fmt,
           register u_int v, const char *sep)
{
        static char buf[256]; /* our stringbuffer */
        int buflen=0;
        register u_int rotbit; /* this is the bit we rotate through all bitpositions */
        register u_int tokval;
        const char * sepstr = "";

        while (lp != NULL && lp->s != NULL) {
            tokval=lp->v;   /* load our first value */
            rotbit=1;
            while (rotbit != 0) {
                /*
                 * lets AND the rotating bit with our token value
                 * and see if we have got a match
                 */
                if (tokval == (v&rotbit)) {
                    /* ok we have found something */
                    buflen+=snprintf(buf+buflen, sizeof(buf)-buflen, "%s%s",
                                     sepstr, lp->s);
                    sepstr = sep;
                    break;
                }
                rotbit=rotbit<<1; /* no match - lets shift and try again */
            }
            lp++;
        }

        if (buflen == 0)
            /* bummer - lets print the "unknown" message as advised in the fmt string if we got one */
            (void)snprintf(buf, sizeof(buf), fmt == NULL ? "#%08x" : fmt, v);
        return (buf);
}

/*
 * Convert a bit token value to a string; use "fmt" if not found.
 * this is useful for parsing bitfields, the output strings are not seperated.
 */
char *
bittok2str_nosep(register const struct tok *lp, register const char *fmt,
           register u_int v)
{
    return (bittok2str_internal(lp, fmt, v, ""));
}

/*
 * Convert a bit token value to a string; use "fmt" if not found.
 * this is useful for parsing bitfields, the output strings are comma seperated.
 */
char *
bittok2str(register const struct tok *lp, register const char *fmt,
           register u_int v)
{
    return (bittok2str_internal(lp, fmt, v, ", "));
}

/*
 * Convert a value to a string using an array; the macro
 * tok2strary() in <netdissect.h> is the public interface to
 * this function and ensures that the second argument is
 * correct for bounds-checking.
 */
const char *
tok2strary_internal(register const char **lp, int n, register const char *fmt,
        register int v)
{
        static char buf[TOKBUFSIZE];

        if (v >= 0 && v < n && lp[v] != NULL)
                return lp[v];
        if (fmt == NULL)
                fmt = "#%d";
        (void)snprintf(buf, sizeof(buf), fmt, v);
        return (buf);
}

/*
 * Convert a 32-bit netmask to prefixlen if possible
 * the function returns the prefix-len; if plen == -1
 * then conversion was not possible;
 */

int
mask2plen(uint32_t mask)
{
        uint32_t bitmasks[33] = {
                0x00000000,
                0x80000000, 0xc0000000, 0xe0000000, 0xf0000000,
                0xf8000000, 0xfc000000, 0xfe000000, 0xff000000,
                0xff800000, 0xffc00000, 0xffe00000, 0xfff00000,
                0xfff80000, 0xfffc0000, 0xfffe0000, 0xffff0000,
                0xffff8000, 0xffffc000, 0xffffe000, 0xfffff000,
                0xfffff800, 0xfffffc00, 0xfffffe00, 0xffffff00,
                0xffffff80, 0xffffffc0, 0xffffffe0, 0xfffffff0,
                0xfffffff8, 0xfffffffc, 0xfffffffe, 0xffffffff
        };
        int prefix_len = 32;

        /* let's see if we can transform the mask into a prefixlen */
        while (prefix_len >= 0) {
                if (bitmasks[prefix_len] == mask)
                        break;
                prefix_len--;
        }
        return (prefix_len);
}

int
mask62plen(const u_char *mask)
{
        u_char bitmasks[9] = {
                0x00,
                0x80, 0xc0, 0xe0, 0xf0,
                0xf8, 0xfc, 0xfe, 0xff
        };
        int byte;
        int cidr_len = 0;

        for (byte = 0; byte < 16; byte++) {
                u_int bits;

                for (bits = 0; bits < (sizeof (bitmasks) / sizeof (bitmasks[0])); bits++) {
                        if (mask[byte] == bitmasks[bits]) {
                                cidr_len += bits;
                                break;
                        }
                }

                if (mask[byte] != 0xff)
                        break;
        }
        return (cidr_len);
}

/*
 * Routine to print out information for text-based protocols such as FTP,
 * HTTP, SMTP, RTSP, SIP, ....
 */
#define MAX_TOKEN       128

/*
 * Fetch a token from a packet, starting at the specified index,
 * and return the length of the token.
 *
 * Returns 0 on error; yes, this is indistinguishable from an empty
 * token, but an "empty token" isn't a valid token - it just means
 * either a space character at the beginning of the line (this
 * includes a blank line) or no more tokens remaining on the line.
 */
static int
fetch_token(netdissect_options *ndo, const u_char *pptr, u_int idx, u_int len,
    u_char *tbuf, size_t tbuflen)
{
        size_t toklen = 0;

        for (; idx < len; idx++) {
                if (!ND_TTEST(*(pptr + idx))) {
                        /* ran past end of captured data */
                        return (0);
                }
                if (!isascii(*(pptr + idx))) {
                        /* not an ASCII character */
                        return (0);
                }
                if (isspace(*(pptr + idx))) {
                        /* end of token */
                        break;
                }
                if (!isprint(*(pptr + idx))) {
                        /* not part of a command token or response code */
                        return (0);
                }
                if (toklen + 2 > tbuflen) {
                        /* no room for this character and terminating '\0' */
                        return (0);
                }
                tbuf[toklen] = *(pptr + idx);
                toklen++;
        }
        if (toklen == 0) {
                /* no token */
                return (0);
        }
        tbuf[toklen] = '\0';

        /*
         * Skip past any white space after the token, until we see
         * an end-of-line (CR or LF).
         */
        for (; idx < len; idx++) {
                if (!ND_TTEST(*(pptr + idx))) {
                        /* ran past end of captured data */
                        break;
                }
                if (*(pptr + idx) == '\r' || *(pptr + idx) == '\n') {
                        /* end of line */
                        break;
                }
                if (!isascii(*(pptr + idx)) || !isprint(*(pptr + idx))) {
                        /* not a printable ASCII character */
                        break;
                }
                if (!isspace(*(pptr + idx))) {
                        /* beginning of next token */
                        break;
                }
        }
        return (idx);
}

/*
 * Scan a buffer looking for a line ending - LF or CR-LF.
 * Return the index of the character after the line ending or 0 if
 * we encounter a non-ASCII or non-printable character or don't find
 * the line ending.
 */
static u_int
print_txt_line(netdissect_options *ndo, const char *protoname,
    const char *prefix, const u_char *pptr, u_int idx, u_int len)
{
        u_int startidx;
        u_int linelen;

        startidx = idx;
        while (idx < len) {
                ND_TCHECK(*(pptr+idx));
                if (*(pptr+idx) == '\n') {
                        /*
                         * LF without CR; end of line.
                         * Skip the LF and print the line, with the
                         * exception of the LF.
                         */
                        linelen = idx - startidx;
                        idx++;
                        goto print;
                } else if (*(pptr+idx) == '\r') {
                        /* CR - any LF? */
                        if ((idx+1) >= len) {
                                /* not in this packet */
                                return (0);
                        }
                        ND_TCHECK(*(pptr+idx+1));
                        if (*(pptr+idx+1) == '\n') {
                                /*
                                 * CR-LF; end of line.
                                 * Skip the CR-LF and print the line, with
                                 * the exception of the CR-LF.
                                 */
                                linelen = idx - startidx;
                                idx += 2;
                                goto print;
                        }

                        /*
                         * CR followed by something else; treat this
                         * as if it were binary data, and don't print
                         * it.
                         */
                        return (0);
                } else if (!isascii(*(pptr+idx)) ||
                    (!isprint(*(pptr+idx)) && *(pptr+idx) != '\t')) {
                        /*
                         * Not a printable ASCII character and not a tab;
                         * treat this as if it were binary data, and
                         * don't print it.
                         */
                        return (0);
                }
                idx++;
        }

        /*
         * All printable ASCII, but no line ending after that point
         * in the buffer; treat this as if it were truncated.
         */
trunc:
        linelen = idx - startidx;
        ND_PRINT((ndo, "%s%.*s[!%s]", prefix, (int)linelen, pptr + startidx,
            protoname));
        return (0);

print:
        ND_PRINT((ndo, "%s%.*s", prefix, (int)linelen, pptr + startidx));
        return (idx);
}

void
txtproto_print(netdissect_options *ndo, const u_char *pptr, u_int len,
    const char *protoname, const char **cmds, u_int flags)
{
        u_int idx, eol;
        u_char token[MAX_TOKEN+1];
        const char *cmd;
        int is_reqresp = 0;
        const char *pnp;

        if (cmds != NULL) {
                /*
                 * This protocol has more than just request and
                 * response lines; see whether this looks like a
                 * request or response.
                 */
                idx = fetch_token(ndo, pptr, 0, len, token, sizeof(token));
                if (idx != 0) {
                        /* Is this a valid request name? */
                        while ((cmd = *cmds++) != NULL) {
                                if (ascii_strcasecmp((const char *)token, cmd) == 0) {
                                        /* Yes. */
                                        is_reqresp = 1;
                                        break;
                                }
                        }

                        /*
                         * No - is this a valid response code (3 digits)?
                         *
                         * Is this token the response code, or is the next
                         * token the response code?
                         */
                        if (flags & RESP_CODE_SECOND_TOKEN) {
                                /*
                                 * Next token - get it.
                                 */
                                idx = fetch_token(ndo, pptr, idx, len, token,
                                    sizeof(token));
                        }
                        if (idx != 0) {
                                if (isdigit(token[0]) && isdigit(token[1]) &&
                                    isdigit(token[2]) && token[3] == '\0') {
                                        /* Yes. */
                                        is_reqresp = 1;
                                }
                        }
                }
        } else {
                /*
                 * This protocol has only request and response lines
                 * (e.g., FTP, where all the data goes over a
                 * different connection); assume the payload is
                 * a request or response.
                 */
                is_reqresp = 1;
        }

        /* Capitalize the protocol name */
        for (pnp = protoname; *pnp != '\0'; pnp++)
                ND_PRINT((ndo, "%c", toupper(*pnp)));

        if (is_reqresp) {
                /*
                 * In non-verbose mode, just print the protocol, followed
                 * by the first line as the request or response info.
                 *
                 * In verbose mode, print lines as text until we run out
                 * of characters or see something that's not a
                 * printable-ASCII line.
                 */
                if (ndo->ndo_vflag) {
                        /*
                         * We're going to print all the text lines in the
                         * request or response; just print the length
                         * on the first line of the output.
                         */
                        ND_PRINT((ndo, ", length: %u", len));
                        for (idx = 0;
                            idx < len && (eol = print_txt_line(ndo, protoname, "\n\t", pptr, idx, len)) != 0;
                            idx = eol)
                                ;
                } else {
                        /*
                         * Just print the first text line.
                         */
                        print_txt_line(ndo, protoname, ": ", pptr, 0, len);
                }
        }
}

void
safeputs(netdissect_options *ndo,
         const u_char *s, const u_int maxlen)
{
        u_int idx = 0;

        while (*s && idx < maxlen) {
                safeputchar(ndo, *s);
                idx++;
                s++;
        }
}

void
safeputchar(netdissect_options *ndo,
            const u_char c)
{
        ND_PRINT((ndo, (c < 0x80 && ND_ISPRINT(c)) ? "%c" : "\\0x%02x", c));
}

#ifdef LBL_ALIGN
/*
 * Some compilers try to optimize memcpy(), using the alignment constraint
 * on the argument pointer type.  by using this function, we try to avoid the
 * optimization.
 */
void
unaligned_memcpy(void *p, const void *q, size_t l)
{
        memcpy(p, q, l);
}

/* As with memcpy(), so with memcmp(). */
int
unaligned_memcmp(const void *p, const void *q, size_t l)
{
        return (memcmp(p, q, l));
}
#endif